In this figure the 4 lines drawn on the mid-sagittal view show the plane of cut for the sections in the figure. In each section, a few of the landmarks that help to identify the level of the section are given. For example, the presence of the colliculi, the cerebral aqueduct and the cerebral peduncle in the section shown in the lower left part of the figure tell you that this section HAS TO BE through the midbrain. However, because the slides in the Cu slide series cut through most of the brainstem at an oblique angle, we will rarely sections that look exactly like these "typical" ones.